BFQ schedules generic entities, which may represent either bfq_queues
or groups of bfq_queues. When an entity is inserted into a service
tree, a reference must be taken, to make sure that the entity does not
disappear while still referred in the tree. Unfortunately, such a
reference is mistakenly taken only if the entity represents a
bfq_queue. This commit takes a reference also in case the entity
represents a group.
Tested-by: Chris Evich <cevich@xxxxxxxxxx>
Signed-off-by: Paolo Valente <paolo.valente@xxxxxxxxxx>
---
block/bfq-cgroup.c | 2 +-
block/bfq-iosched.h | 1 +
block/bfq-wf2q.c | 12 ++++++++++--
3 files changed, 12 insertions(+), 3 deletions(-)
diff --git a/block/bfq-cgroup.c b/block/bfq-cgroup.c
index cae488b58049..09b69a3ed490 100644
--- a/block/bfq-cgroup.c
+++ b/block/bfq-cgroup.c
@@ -332,7 +332,7 @@ static void bfqg_put(struct bfq_group *bfqg)
kfree(bfqg);
}
-static void bfqg_and_blkg_get(struct bfq_group *bfqg)
+void bfqg_and_blkg_get(struct bfq_group *bfqg)
{
/* see comments in bfq_bic_update_cgroup for why refcounting bfqg */
bfqg_get(bfqg);
diff --git a/block/bfq-iosched.h b/block/bfq-iosched.h
index 2c7cec737b2a..d1233af9c684 100644
--- a/block/bfq-iosched.h
+++ b/block/bfq-iosched.h
@@ -985,6 +985,7 @@ struct bfq_group *bfq_find_set_group(struct bfq_data *bfqd,
struct blkcg_gq *bfqg_to_blkg(struct bfq_group *bfqg);
struct bfq_group *bfqq_group(struct bfq_queue *bfqq);
struct bfq_group *bfq_create_group_hierarchy(struct bfq_data *bfqd, int node);
+void bfqg_and_blkg_get(struct bfq_group *bfqg);
void bfqg_and_blkg_put(struct bfq_group *bfqg);
#ifdef CONFIG_BFQ_GROUP_IOSCHED
diff --git a/block/bfq-wf2q.c b/block/bfq-wf2q.c
index 26776bdbdf36..eb0e2a6daabe 100644
--- a/block/bfq-wf2q.c
+++ b/block/bfq-wf2q.c
@@ -533,7 +533,9 @@ static void bfq_get_entity(struct bfq_entity *entity)
bfqq->ref++;
bfq_log_bfqq(bfqq->bfqd, bfqq, "get_entity: %p %d",
bfqq, bfqq->ref);
- }
+ } else
+ bfqg_and_blkg_get(container_of(entity, struct bfq_group,
+ entity));
}
/**
@@ -647,8 +649,14 @@ static void bfq_forget_entity(struct bfq_service_tree *st,
entity->on_st_or_in_serv = false;
st->wsum -= entity->weight;
- if (bfqq && !is_in_service)
+ if (is_in_service)
+ return;
+
+ if (bfqq)
bfq_put_queue(bfqq);
+ else
+ bfqg_and_blkg_put(container_of(entity, struct bfq_group,
+ entity));
}
/**
--
2.20.1
